Wave-particle Interactions in the Plasmaspheric Plume and the Ring Current Dynamics

For many years, various plasma wave-particle interactions in the ring current region have been theorized and simulated, though satellite observations have been limited. This study seeks a deeper understanding of the nuances present and dynamics of warm ions and ring current plasma in the inner magnetosphere through analysis of the simultaneous in situ particle and wave measurements from the Van Allen Probes (RBSP) mission and simulation results from the Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model. For this study, we investigate the increase in ion fluxes inside the plasmasphere and plume region during a geomagnetic storm. We find lower band chorus emissions directly outside the plasmapause as well as plasmaspheric hiss inside the plasmasphere. We apply a Fast Fourier Transform to the EMFISIS fluxgate magnetometer measurements of the magnetic field to analyze the magnetic field spectrogram for frequencies less than 10 Hz. Van Allen Probe A and B report multiple Electric Magnetic Ion Cyclotron (EMIC) wave events directly inside the plasmasphere plume as well as outside the plume boundary, which corresponds to increased perpendicular fluxes for H+ and He+ ions at those times. Between the plasmapause and plasmasphere plume region, we also identify magnetosonic waves and electron Bernstein mode waves. The plasmasphere plume density gradient acts as a wave guide for magnetosonic waves, trapping the waves between the plasmasphere and plume. We discuss various heating mechanisms, and suggest that the perpendicular heating of the warm H+, He+, and O+ ions during this time is a consequence of interacting with magnetosonic waves triggered by the ring current injections as well as energization by the jumps in the convection strength associated with the substorm activity.